1. Field of the Invention
The present invention relates to apparatus for allowing an operator to apply liquid adhesive to the side edges of a component piece of a plastic package, and more particularly to an apparatus for application to all or selected edges of a generally rectangular clear plastic piece.
2. Description of the Prior Art
Today it is quite common to find small articles for sale packaged in clear plastic xe2x80x9cshellsxe2x80x9d or packages that secure their contents while allowing them to be visually displayed for the benefit of the shopper. Such packages can have two separate components, a lid and a bottom piece, or can be a xe2x80x9cclamshellxe2x80x9d type package where the two components, lid and bottom, are attached along one edge by an integral xe2x80x9cliving hingexe2x80x9d of material. Another popular package has a tubular sleeve that is sealed with rectangular end caps. See FIGS. 1-3 for illustrations of these package examples.
During the packaging process it is often necessary to apply adhesive to four sides of a piece. In other cases, such as with clamshell type packages, adhesive is applied to at least the edge opposite the living hinge, or to all three available edges for increased security.
The conventional way of applying adhesive is directly from the tip of a hand-held bottle dispenser, or by brush, roller or other manual applicator. Unfortunately such techniques suffer from inconsistency and waste; i.e. the application can often be insufficient or excessive, as well as uneven. It is also noted that the quality of application will vary from one operator to the other. This can result in the scrapping of packages, or finished packages lacking the desired clean even finished look.
The problem of wasteful and inefficient glue application is particularly important where relatively expensive adhesives are used such as in UV-activated liquid adhesive systems.
In view of the foregoing it is a general object of the present invention to provide an improved apparatus and method for applying liquid adhesive to edges of a plastic package component.
A more specific object is to provide an apparatus that will allow an operator to apply a desired thin, even deposit of adhesive in a quick reliable and consistent manner.
A further object is to provide an efficient method and apparatus that will minimize packaging costs.
Yet another object is to provide for a sealed finished package that has a clean, clear even look.
A further object is to provide apparatus that can be configured for application of adhesive to one, two, three or all four sides of a rectangular package component, as desired.
These and other objects and advantages are provided by the present invention of apparatus for applying adhesive to the outer edges of a generally rectangular package component, the invention having an upper portion and a lower portion. The lower portion comprises a reservoir for holding liquid adhesive and the upper portion features a rectangular top plate with a smooth flat top surface.
There is a least one pair of opposing transverse slots and longitudinal slots in the top plate, arranged in a rectangular configuration.
The invention further includes adhesive wick assemblies that can be removably installed in the slots, each wick assembly having an elongate upper portion which projects a predetermined distance above the plate top surface when said assembly is installed in the slot, and a lower portion that extends downwardly into the confines of the reservoir.
When a wick assembly is mounted in all four slots, the upper parts of the assemblies provide a rectangular border around a rectangular space on the top plate.
In operation, liquid adhesive from the reservoir will be drawn up to wet the exposed upper parts of the wick assemblies, and a package piece that is smaller than the opening is placed in the opening with the piece bottom slidably supported by the top plate. The operator can then use a simple xe2x80x9ccircularxe2x80x9d motion to move the sides of the piece into successive engagement with each of the wetted wicks.
In one embodiment of the invention the wick assembly comprises an elongate support bar and a felt-like wick member that is looped around the support bar.
Another embodiment has slots along the perimeter of the top plate, and additional transverse and longitudinal slots are provided in the major surface of the plate. Thus the invention allows wick assemblies to be arranged to accommodate a variety of package sizes and to apply adhesive to selected edges of the piece.